! Copyright (c) 2012 Anonymous
! See http://factorcode.org/license.txt for BSD license.
USING: io kernel math math.parser ranges sequences ;
IN: rosetta-code.multiplication-tables

! http://rosettacode.org/wiki/Multiplication_tables

! Produce a formatted 12×12 multiplication table of the kind
! memorized by rote when in primary school.

! Only print the top half triangle of products.

: print-row ( n -- )
    [ number>string 2 CHAR: space pad-head write " |" write ]
    [ 1 - [ "    " write ] times ]
    [
        dup 12 [a..b]
        [ * number>string 4 CHAR: space pad-head write ] with each
    ] tri nl ;

: print-table ( -- )
    "    " write
    1 12 [a..b] [ number>string 4 CHAR: space pad-head write ] each nl
    "   +" write
    12 [ "----" write ] times nl
    1 12 [a..b] [ print-row ] each ;